Page 2 Vintage Stereo Receivers ~ Tuners ~ Amps

Pioneer SX-1250

Pioneer SX-1250 bench nudies

Pioneer SX-1250

('76-'78) 160 WPC $2650

In excellent cosmetic and *operating condition, this Pioneer SX-1250 had extensive servicing done in November 2024 that included a laborious disassembly. To properly get to the pots and switch assemblies, it's necessary to pull them out in order to get to each individual section. It's a tedious process but it simply has to be done. The filter caps are still within spec. The bias adjustment was done. This receiver has not been recapped and, in our opinion, does not need to be done at this time. We will leave that up to the next owner to decide.
*NOTE: absolutely everything works perfectly, the only issue is that the FM only works in mono.
The service was followed up with thorough cleaning, more checking and finally, 8 hours of continuous operation with no issues.

Although there is a lot of information out there regarding this excellent, 65 lb monster receiver, here's the basics:
The SX-1250 was introduced in 1976 as Pioneer's top of the line receiver. It reflected Pioneer's new styling of matching silver tuning dial with white background signal strength and stereo signal meters.
It puts out a minimum of 160 watts per channel into 8 ohms and a thundering 200 watts per channel into 4 ohms . It originally sold for $900.00 back then.

Features:
Tone on/off (which turns off the bass, treble controls), filters 30hz and 8khz, tape duplicate switch, FM muting on/off FM multipath, Adaptor on/off (which allows you to hook an equalizer up etc.) mic left/right inputs, two tape in/outputs, one aux input, two phono inputs, phono two switch is for both mic and phono two, modes stereo and mono, and both tuning and signal meters.

From the web:
"Considered by many to be the best receiver/amplifier of the 1970s (translates best-ever – period!) the Pioneer SX-1250 was the top-of-the-line model for the 1976-1977 Pioneer Receiver range. A product of the “Receiver Wars”, no expense was spared in the design and engineering of this model and this is evident in the specifications, build quality and performance.

Pioneer developed the now legendary power section of the SX-1250 with completely independent power supplies, including separate power supply windings, rectifiers and smoothing capacitors for each channel, the components of which include a massive 22 pound toroidal core transformer (less susceptible to power fluctuations and less likely to create noise than laminated core transformers) and four ‘Coke Can’ size 22,000uf filter capacitors"

Basic specs:
Power Output: 160 watts per channel RMS into 8 ohms
200 watts per channel RMS into 4 ohms
THD: Less than 0.1%
Dimensions: 22"W x 7.5"H x 18.75"D
Weight: 64.25 lbs

Back story:
The 1976 Pioneer SX-1250 set the audio world on its ears in when it was introduced in 1976. All of a sudden, Pioneer Electronics was now the Top Dog in the mainstream audio world. It was a true breakthrough product with exceptional build quality, and, even today it commands respect. With all discrete components, it's relatively easy to repair and finally, it's just friggin' handsome!
Pioneer SX-1010 was the top model before the SX-1250, has signaled the start of the legendary "Power Wars" in 1975, where most of the audio manufacturers of that time attempted to outdo each other with progressively more powerful receivers, reaching outlandish sizes and power outputs. The 1010 also marked the ascendency of the Japanese auto industry which had not been taken very seriously before it arrived. The 1010 was quickly topped by the Marantz 2325, then the Sansui 9090 and the Kenwood KR-9400. So, Pioneer, not to be outdone by its erstwhile rivals, struck back convincingly with the SX-1250. It was a big jump. The 1250's "all Silver" look quickly took hold and was shamelessly copied by all the other manufacturers. The "Blue Light" era of the SX-1010 and Marantz 2325 was officially over!

But, the SX-1250 was about much, much more than mere cosmetic ruffles. First, and foremost, IT WAS BUILT LIKE A TANK! It was, and still is, considered one of the best built receivers of all time. Its massive Toroidal Transformer power supply is still regarded as one of the best ever, with four hulking 22,000 uf filter capacitors. In fact, even though the subsequent SX-1280 was rated at 185 wpc, 20 wpc more than the SX-1250, the 4 filter caps in the SX-1280 were only 15,000 uf. And the 270 watt per channel SX-1980 had essentially the same power supply as the SX-1250, making the 1250 considerably over-engineered relative to its rated power and leaving the SX-1980 was left with very little dynamic range beyond its rated power.
The construction quality of the SX-1250 was simply superlative with heavy shielding over every section. This attention to detail had not been seen in receivers before. This was surely the height of Japanese construction quality. And, the specifications of the SX-1250 were competitive with some of the finest separates of the time. All in all, the 1250 was a "tour de force". That's why so many owners swear by it after having owned it almost 40 years!
Some have said that the styling for the 1250 is very conservative and, for that very reason, it has held up quite well.

Pioneer SA-7100

Pioneer SA-7100 bench nudies

Pioneer SA-7100

integrated amp ('73-'76) 20 WPC @ 8 / 24 WPC @ 4 $450

Obtained from the original owner, this Pioneer SA-7100 was best described as their "advanced stereo integrated amplifier." In excellent cosmetic condition, it has been extensively serviced, thoroughly tested and is fully operational. It includes the factory walnut veneer case. This particular amp is one of their dual voltage units.

Most of the reviews for the SA-7100 agreed it was "practically overbuilt" considering its modest power rating of 20 watts per channel into 8 ohms (24 WPC into 4 ohms). The superior build quality of this low powered integrated amp basically stumped the competition at first. Everyone scrambled to try and figure out how Pioneer could build this kind of equipment at such a competitive price. It has outputs for two turntables, two auxiliary, two tape PLUS it has jumpers for pre-out/amp as well! That was an incredible amount of features for "just" a 20 watt-per-channel unit.

For those that look at just watts, you'd be missing out on what this superb integrated amp can handle. Features include a 3-stage direct coupled equalizer section, FET equipped tone control amplifier section, turnover frequency selectors and a reliable automatic protection circuit.

Pioneer recommended the SA-7100 in its 1974 catalog as “an extremely user-friendly modern HiFi amplifier”. Additionally, in the case of this model, we cannot forget about the pleasure of use, considering its beautiful simple brushed aluminum panel and high quality knobs and switches.

During its very successful production run, Pioneer could point to the SA-7100 as a perfect example why they were number one in sales during the fiercely competitive 70's (otherwise known as the "Golden Age of HiFi".)

Basic specs:
Power output: 20 watts per channel @ 8 ohms / 24 WPC @ 4 ohms
Frequency response: 7Hz to 80kHz
THDn: 0.5%
Dimensions: 17"W x 6"H x 13.5"D
Weight: 23 lbs

About Pioneer...
Not much needs to be said about Pioneer other then the simple fact that the name is known worldwide for above average quality and excellence in high fidelity component design. They were the unchallenged leader in stereo advertising and marketing in the 70's. Back in the day, Pioneer made it clear that if you didn't have a Pioneer stereo system in your house (or college dorm) you just didn't have the right stuff.

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Yamaha CR-1040

('79-'81) 100 WPC into 4 ohms $700 (perfect)

In stellar cosmetic condition and fully operational, this beautiful Yamaha CR-1040 has been completely and carefully serviced. The protection circuit has new transistors and the tone board has been partially recapped. The meters have been calibrated. It has been upgraded with the very desirable "cool green" lamps across the faceplate glass. The gorgeous dark rosewood veneer cabinet appears as new. It's truly a gorgeous receiver when viewed in person. Photos just don't do it justice.

The most likely King of the Yamaha family at the time was the CR-2040 but the "Prince" is probably the CR-1040. You might get some arguments from owners of the CR-1020 but the CR-1040 could probably be considered a bit of an upgrade given its size and higher power output. In 1979 it retailed for close to $500 which was a hefty sum of money back then. Underrated at 80 watts per channel into 8 ohms and a solid 100 watts per channel into 4 ohms, it has less than 0.02% THD.

Many would say that the CR-1020 is a better looking receiver but that the CR-1040 has a better sound? These are discussions that go and on. Besides, it's almost always about the speakers anyway.
Some of the best features are the inputs for either MM or MC phono connections and adjustable cartridge matching. Also the unique triple meters that can switch from L/R power meters or FM tuning and signal strength.

The CR-1040 is one of Yamaha’s “Natural Sound” receivers and when one usually listens to one of these receivers for the first time it may sound as though it’s lacking a little in bass. The reality most likely is that other receiver manufacturers “color” their circuitry to emphasize more bass so that’s what many listeners are used to hearing. The Yamaha circuitry does not do this so you are hearing the sound closer to how it is actually supposed to sound.

That's where Yamaha's famous *continuously variable loudness control comes in. Among Yamaha's most significant features is the continuously variable loudness control. By using this control, the frequency balance and volume are adjusted simultaneously to compensate for the ear's insensitivity to high and low frequency sound at low volume settings. Thus, you can retain a natural-sounding balance regardless of listening level.
*NOTE: How does Yamaha's Loudness control work?
Theoretically, the degree of loudness compensation should vary with the listening level: The greater the reduction from "real" sonic levels, the greater the compensation. In the Yamaha CR-1040, you first turn up the loudness all the way and set the volume control to the highest listening level you'd be likely to want, which will, of course, depend on your taste, the efficiency of your speakers and the acoustics and size of your room. For subsequent level adjustments, turn down the loudness, which boosts the lows and, to a smaller extent, the extreme highs relative to the midband to maintain a natural sounding balance.

Main features:
Triple tone controls with variable contours for each
Variable loudness
Meter: Level / Signal
Filters: High, Low
Phono selector: MC/MM/33/47/68/100 kOhms
3 extra power outlets, switched / unswitched

Basic specs:
Dimensions: 23"W x 16"D x 6.5"H
Weight: 37 lbs

About Yamaha...(1972 and later)
One of the most famous brands in the world, Yamaha had its fingers in so many different products...yet somehow managed to carve out a healthy slice of praise from audiophiles in regards to their electronics. From the incredible Yamaha CA-1000 integrated amp that whipped up a whirlwind and brought Yamaha recognition in the audio world, to the AX-2000A amp that, after groping around with digital technology, managed a comeback to pure analog. The very successful "Natural Sound" marketing in the 70's brought Yamaha into direct competition with Pioneer, Marantz and almost all the other great companies of the era.

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Adcom GFA-535/II

stereo amp (1993) 60 WPC $300

In near mint cosmetic condition and working perfectly, this Adcom 535/II amp is about as good as it gets for the money spent. It's fully serviced and comes with the original factory owner's manual and box.

When first introduced in 1987, the affordable price (relative to actual performance) was shocking to some in the audiophile community. So much so that it threw some people off; it didn't make sense that an amp of this quality could be so inexpensive when compared to the competition.
True, they did increase the price a few times until the end of production but the mere fact that any models like these could have a successful production run of so many years, in such a hot competitive amp market is still amazing.

While the GFA-535/II is rated at 60 watts per channel, it's built-in headroom puts out more like 80 watts per channel. At this point in time (the mid 80's) it seemed that Adcom's customers wanted Adcom's GFA-555 with 200 watts per channel at $200 more than the GFA-535/II. But did the GFA-555 sound any better? Adcom said "it's our aim to have all our amps sound pretty much the same. You pay more money, you get more power."

Because the markets (and consumers) seem to always need the "new and improved" model, Adcom replaced the GFA-535 with the 535 II. So, how much was it improved? Not much really. The innards and power output are basically the same, a few cosmetic tweaks (mainly the style of the inputs on the back) here and there but, essentially, both versions are excellent.

Stereophile Dec 1987
"The Adcom GFA-535 is one of the finest solid-state amps I have heard. No, not the best; I'm not sure what is the best. But it's an amplifier that is so good for so little money as to be practically a gift. In its price category, the Adcom GFA-535 is not only an excellent choice; it's the only choice. The real question is whether you should buy one even if the cost is much less than you planned to spend for an amp—ie, whether you should put the money into a better CD player or pair of speakers instead."

Specs:
Output power: 60W into 8 ohms
Input sensitivity: 970mV RMS.
Input impedance: 100k ohms.
Frequency response: 10Hz–20kHz, –0.25dB.
S/N ratio: 110dB. (power consumption: 300 watts)
Dimensions: 3"H x 17"W x 11.25"D.
Weight: 19.5 lbs.

Adcom GFP-565

preamp ('89-'98) $500

In perfect operating and cosmetic condition, this Adcom GFP-565 preamp is one of their more highly rated units.

No doubt, the world is filled with excellent, high quality stereo amps but, essentially, they are useless without an equally excellent pre-amp. An amp is merely a chunk of power waiting for the preamp to spread that power in a direct and satisfying manner.
In this aspect, the GFP-565 is a sensible and smart companion to almost any high quality amp. Included is the original factory owner's manual.

The GFP-565 has three sets of outputs: Main (Normal and Lab) and Bypass. Although the tone controls can be switched out of circuit when the preamp is used from its Main outputs, the Bypass outputs omit all the tone control and feature switching and are recommended for the best sound quality.

The GFP-565 can either offer a Class B or a Class C sound, depending on whether its owner wants to use it as a basic, no-frills preamplifier via its Bypass outputs, or as a full-featured control center via its Main outputs.

Basic specs:
Frequency response: 5Hz to 90kHz
THD: 0.0025%
Dimensions: 17"W x 12.5"D x 3.3"H
Weight: 11 lbs

Adcom GFA-555MS

power amp (2011) 200 WPC $700

In perfect operating and cosmetic condition, this Adcom GFA-555ms pumps out 200 watts into 4 ohms.
It takes both unbalanced and balanced inputs and drives your speakers with 125 watts per channel (into 8 ohms) of high performance, ultra low distortion power output all from a neat package.
Technically speaking, Adcom engineered an uncompromised circuit design that delivers ultra-low distortion and a crisp dynamic sound. Great care was taken to ensure that distortion in the 555MS would remain extremely low, particularly when driving these highly reactive loads in which the phase angles of the voltage and the current are substantially different.

Basic specs:
125 watts into 8 ohms
200 watts into 4 ohms
Frequency Resp: @ 1watt, 8-ohms: +0. -0.25dB, 10Hz to 20kHz
Power Bandwidth (-3dB): 10Hz to 100k
Dimensions: 6”H x 17”W x 12.5”D
Weight: 28.6 lbs.

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Heathkit AA-1214

Heathkit AA-1214 bench nudies

Heathkit AA-1214

integrated amp (1973) 20 WPC @ 4 ohms $150 (partial recap)

Simplicity defined: This Heathkit AA-1214 integrated amp is small in size but, since the power board has been recapped, it's certainly capable of driving most any pair of efficient bookshelf speakers.
It's rated at a nominal 15 watts per channel into 8 ohms and about 20 watts per channel into 4 ohms. All the inputs and outputs are fully functional.
The cosmetics could be better but since part of the lettering over the volume and balance knobs has worn away, it is what it is. Regardless, the faceplate glass, original knobs, real timberwood side panels and textured metal top are all in very good condition.

This is an inexpensive way to get going on a vintage system with the Heathkit providing a solid anchor. As mentioned above, it's all about the right choice of speakers.

Basic specs:
Dimensions: 17"W x 3.9"H x 13"D
Weight: 14 lbs

About Heath...
There once was a time in electronics when you could actually build circuits and equipment yourself. You needed a design that you could create yourself—or if not, get from one of many magazines, including Electronic Design. You could buy the resistors, capacitors, transistors, or tubes in the olden days, then put them all together on a metal chassis, a breadboard, or a finished printed-circuit board (PCB). It was quite a project but doable, and many hobbyists like hams built these designs on a regular basis.

In the late 1940s and 1950s, someone invented the kit business. Companies designed a product and sold it as a bundle of parts called a kit. You could buy the kit for a fraction of what a comparable wired unit would cost and then build it yourself. The outcome was quite favorable—a workable electronic product and a great sense of accomplishment you got from the construction.

Heath was one of those companies that helped start the kit business. Ed Heath founded the company in 1926 with, of all things, an airplane kit. He died in a test flight in 1935, but Howard Anthony kept the company going. Right after World War II, he bought a batch of electronic surplus. Out of that came one of the first successful kits, a small oscilloscope for $50, which was a real achievement in its time. With that success came many new products.

Heathkit probably succeeded more on its ham radio products than anything else. Most of the early kits were shortwave radios, transmitters, accessories like antenna tuners, and the famous Cantenna, a 1-kW non-inductive power resistor in a paint can with mineral oil for the heatsink. Heathkit went on to create an extensive line of small and large transceivers and big power amps, many of which are still operational today.

The Successful Years

Later in the 1950s and 1960s, Heathkit expanded into audio equipment, TV sets, and lots of other consumer products. The company even had a low-cost line of test equipment with scopes, multimeters, generators, counters, and other items. While Heathkit had competitors like Allied Knight, Lafayette, Eico, and a few other smaller companies, it essentially beat the pants off everyone else because it had a better product.

But Heathkit’s good reputation really came from offering a better assembly manual than anyone else. A poorly executed step-by-step manual is a prescription for disaster for any kit company. If the customer can’t build the kit successfully without massive telephone and mail support, it would die a quick death, and many did. Heathkit figured this out early and spent as much development time in the manual as it did engineering the product. Its primary marketing message was “We won’t let you fail,” and the company lived up to it.

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Toshiba SA-775

('78-'79) 75 WPC / 105 WPC $700

We are fortunate to have obtained this massive Toshiba SA-775 receiver because they are as rare as hen's teeth. Cosmetics are excellent. The walnut veneer case is very clean and the metal vent was removed, stripped, sanded and refinished with a beautiful metallic soft iron coating.

On the inside, this unit has been completely disassembled and thoroughly serviced. Bias and DC offset was set, every input, output, switch and lamp is operating perfectly.

Second to the TOTL SA-7100, the SA-775 was one of the big (literally) Toshiba receivers that were way under-appreciated by the vintage HiFi community until they were discovered to be of much higher quality than previously thought. They sometimes don't bring the higher prices as some of the more well known brands but, regardless, they were definitely very well built and sound fantastic.

The SA-775 puts out a minimum 75 watts per channel into 8 ohms and a hefty 105 watts per channel into 4 ohms. It has a neat flip-open door on the lower section of the faceplate for the tone / balance controls and switches. Overall the SA-775 has a very handsome exterior design and excellent performance. The four large backlit meters have new LEDs. When viewed in person, the SA-775 is substantially larger than most of the competition in their class.
Tech info from Toshiba:
With a parallel push-pull connection and low noise design, the SA-775 has two independent power supplies with completely separate transformers for the tuner and class A operation preamp on the one hand, and the power amp, where power supply voltage fluctuates with output signal level, on the other. This results in clear undistorted sound by preventing transient distortion arising from power supply fluctuation feeding back to the preamp when output levels change.

Furthermore, transient response characteristics have been improved by lowering power supply impedance thanks to the use of 15,000uF caps and large transformer.

This volume control is a 32-step precision attenuator type. Two-step audio muting adds to fine volume adjustment capability.

In the phono equalizer section, a high phono overload level of 350mV is attained with a ±35V high voltage power supply while RIAA deviation is kept to a mere ±0.2 dB by means of precision components. Phono S/N level is a high 80dB thanks to strictly selected low noise transistors.

Not only is the unit protected against shorted speaker terminals, the speakers themselves are also protected by a circuit that operates should DC drift appear in the amplifier. Furthermore, relay operated muting prevents disturbing speaker noise when the power is turned on and off.

The left and right channel output power meters feature logarithmically compressed scales that allow direct readings from lowest to highest levels.

The advanced front-end design, incorporating MOS FET, RF amplifier, and a 4 ganged frequency linear variable capacitor provides extremely high sensitivity and low intermodulation distortion.

Basic specs:
Frequency response: 20Hz to 20kHz
THD: 0.05%
Speaker load impedance: 4 ohms (minimum)
Dimensions: 22"W x 7.5"H x 18.1"D
Weight: 41 lbs

About Toshiba...
Today, most recognize the name Toshiba primarily because of its monster class SA-7150 with its massive power at 150 watts per channel. But, back in the early 70s, when HiFi dealers took on the Toshiba audio product lines, the salesmen considered them a second-level product line to the Marantz, Pioneer, Sony , etc. However, as time went on and technicians began to open them to see inside, they spread the word and slowly, people started to change their minds.

At the time, most Toshiba, Sanyo and other similar brands were associated with clock radios, and similar little devices that showed up in various stores that normally didn't sell hifi gear.

For the dealer, Toshiba was agressively priced so that there was better margin in their products, which translated to higher profits. This was because Toshiba didn't advertise or get product reviews from the audio magazines. Today, this explains why Toshiba is less known in general about the very good quality in their stereo equipment.
In fact, their gear was quite good, performed as good as the big-name gear and still does today - when you can find them. Because of their low key marketing stance, it's doubtful their sales volumes were anywhere near those of Sony, Pioneer, etc.

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